comparison of analytical & fea of contact analysis of spur gear drive

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056

Volume: 03 Issue: 09 | Sep -2016 www.irjet.net p-ISSN: 2395-0072

© 2016, IRJET | Impact Factor value: 4.45 | ISO 9001:2008 Certified Journal | Page 620

COMPARISON OF ANALYTICAL & FEA OF CONTACT ANALYSIS OF SPUR

GEAR DRIVE

Sachin Almelkar1, Prof I.G.Bhavi2

1M.Tech (Machine Design). B L D E A’s Dr.P.G. Halakatti College Of Engineering and Technology,Vijayapur, Karnataka, India

2Assistant Professor Department of Automobile Engineering, B L D E A’S Dr.P. G. Halakatti College Of Engineering and Technology, Vijayapur , Karnataka, India

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Abstract : The contact stress in the mating gears is the key parameter in gear design. This paper presents the contact stress analysis of the spur gear pair as first gear in the gearbox of Tata LPT 1112 truck to find maximum stress in the gear teeth. The contact stresses obtained from theoretical Hertz equation values are compared with the Finite Element Analysis (FEA) method. For the analysis, 17-4 PH steel, Brass and Aluminium are used as the materials of the spur gear. The spur gears are modeled and assembled in the CATIA V5 software and FEA is carried out using ANSYS 13.0 software. The results show that the contact stress obtained from theoretical Hertz equation is very less when compared to FEA results hence, both results are comparable.

Key words: Contact stress, ANSYS, Spur gear, Hertz Equation, FEA.

1. INTRODUCTION

Gears are widely used in all type of machineries in industry. Ever since gear was known over 3500 years before, they become the integral part of every machine. The initial gear drives were simple and rod inserted mounted axially. They used to transmit rotational force or circular motion from one part to another. Pair of gears is used with lower speed cycle. The main difficulty by this system is when the loads and speed were raised the contact stresses were generated at the tip of contact where materials could not withstand these type of stresses due to high wear and contact area. In gear pairs, the larger one is named as gear and smaller one is called pinion. When pinion acts a driver, it gives step down and results in increase in torque and decrease in the output speed. Gear acts as a driver; it results in step up drive and gives an output in decreases in torque and increase in output speed. Gears are used to create variation in the speed of rotation and to move rotational motion to different-axis.

Vivek Karaveer, Ashish Mogrekar and Preman Reynold Joseph explained analysis of stress of spur gear to find maximum contact stress in the teeth. They compared FEA analysis results with hertz contact equation for the materials grey cast iron and steel. They have created model in ANSYS Design Modeler and analysis is done using ANSYS software. They have concluded that stress values of steel and grey cast iron gear are comparable. S Mahendran, K M Eazhil, and Senthil Kumar they have studied the weight reduction and stress distribution, Impact analysis, torque loading of cast steel and composite materials for Tata Super Ace Model. Modeling of gear is done using SOLIDWORKS software and analysis is done using ANSYS software. They have compared and analyzed composite gear with cast steel. They have concluded that stress values, deformation and weight of the spur gear for composite material are less than cast steel.

Table – 1: Material properties

Property 17-4 PH steel

Brass Aluminium

Density (g/cm3) 7.78 8.4 2.70 Young’s

modulus (GPa) 196 105 70

Poisson’s ratio 0.136031 0.357 0.3

2. OBJECTIVE

The main objective of this work is to carry out the contact stress analysis of the spur gear pair as first gear in the gearbox of Tata LPT 1112 truck. The contact stresses obtained from theoretical calculations are compared with the finite element analysis method. The analysis is carried




out for different materials like 17-4 PH steel, Brass and Aluminium

3. PROJECT DESCRIPTION

3.1 Design of spur gear

The modeling is done using CATIA V5 software. The maximum contact stress of spur gear is determined during the transmission of Torque of 400N-m by using 17-4 PH steel, Brass, Aluminium materials, using finite element analysis.

Table - 2: Dimensions of spur gear Pinion Gear

Pitch circle diameter (mm)

64 76

Face width (mm) 20 20

Number of teeth 32 38

Pressure Angle (0) 200 200

Fig-1: Assembly of spur gear drive set

4.2 Specifications and Design calculations

Table-3: Specifications

Model TATA TRUCK

Engine TATA LPT 1112 Truck (BS )

Engine capacity 3733cc

Maximum Power 125HP or 92KW

Maximum Torque 400Nm @ 1300-1500rpm

Maximum Speed in Top Gear

83Km/hour

Calculations

Gear Ratio =

=

=

=

NG = 1263.1579rpm

Torque (pinion) = Force Distance

400Nm = F 32mm

F = 12500N

Using Lewis equation,

Tangential load, F = b*y*Pc*

Y=0.134mm, F=12500N, Pc=6.2831mm, b=20mm

The maximum allowable stress 742.3272Mpa

Ultimate tensile strength for 17-4 PH steel is = 1030Mpa

Allowable stress for cast steel = ultimate tensile strength/1.2

=1030/1.2 = 858.33Mpa > 742.3272Mpa

So, the design is safe.

4. Theoretical calculation of contact stress (Hertz equation)

Contact stress for 17-4 PH steel material

√

= √

= 1828.480MPa

5. Finite Element Analysis

5.1Meshing In FEA analysis the computational domain is

discretized into number of elements and the nodes of the elements are known as grid points. The process of




discretizing the domain is called meshing. Fine Meshing is done with the size of 3mm.

Fig-2: Typical view of meshed spur gear

5.2 Boundary condition

Frictionless support is applied on inner rim of the pinion and Frictionless support is applied on inner rim of Gear. Moment of 400 N-m is applied on the pinion in anticlockwise direction as the driving torque.

Fig-3: Boundary conditions on spur gear drive

Fig-4: applying moment to pinion

6. Results and Discussion

6.1 FEA results of 17-4 PH steel

Fig-5: Equivalent (Von-Mises) stress

Graph no-1 Moment vs Von-mises stress for steel and steel




6.2 FEA results of Brass

Fig.6 Equivalent (Von-Mises) stress

Graph no-2 Moment vs Von-mises stress for Brass and Brass

6.3 FEA results of Aluminium

Fig-7: Equivalent (Von-Mises) stress

Graph no-3 Moment vs Von-mises stress for Al & Al

Table - 4: Comparison of contact stress obtained from Hertz equation with FEA results.

Material Contact stress (MPa)

ANSYS Hertz Error

17-4 PH steel 1871.7 1828.48 2.36%

Aluminium 1167.9 1460.8 1.839%

Brass 1460.8 1419.40 2.916%

Graph no-4 Moment vs von-mises stress for Steel,

Brass & Aluminium




7. CONCLUSION

The difference between theoretical contact stress results of spur gear drive and FEA results are very less. Hence both results are comparable. The theoretical Von-mises stress of 17-4 PH steel & FEA results of 17-4 PH steel are comparable. Similarly the theoretical contact stress of Aluminium, Brass material and FEA results are comparable. We conclude that the stress induced in the 17-4 PH steel material is higher than Brass and Aluminium and stress induced in the Brass material is higher than Aluminium therefore we suggest that aluminum material is best suited to minimize the stress in the gear drive.

8. REFERENCES

1. VivekKaraveer, AshishMogrekar and T. PremanReynold Joseph “Modeling and FEA analysis of Spur Gear” International Journal of Current Engineering and Technology Vol.3, No.5, December-2013.

2. S Mahendran, K M Eazhil, and Senthil Kumar“ Design and analysis of composite spur gear” IJRSI Vol.1, Issue.6, November 2014.

3. Aakanksha M. Garud, V.G. Bhamare“Various Approaches For Analysis of Spur Gear To ReduceContact Stresses On Gear Tooth” International Journal of Engineering, Education and Technology Vol.3, Issue.2, April 2015.

4. Shanavas S. “Stress analysis of spur gear” International Journal of Engineering Research & Technology Vol.2, Issue.12, December 2013.

5. M Keerthi, K Sandya, K Srinivas“Static and dynamic analysis of spur gear using different materials” International Research Journal of Engineering and Technology” Vol.3, Issue.1, Jan 2016.

6. Putti SrinivasRao, NadipalliSriraj, and Mohammad Farookh “Contact stress analysis of spur gear for different materials using ANSYS and Hertz equation” International journal of Modern Studies in Mechanical Engineering, Vol.1, Issue.1, June 2015.

7. Utkarsh M Desai, Dhaval A Patel “Modeling and stress analysis of composite material for spur gear under static loading condition” ISSN, Vol.1, Issue.2, 2015.

8. Mohammad Jebran Khan, ArunishMangla, and SajadHussain Din “Contact stress analysis of stainless steel spur gears using FEA analysis and comparision with theoretical results using hertz theory” International Journal of Engineering Research & Applications, Vol.5, Issue.4, April 2015.

9. Bharat Gupta, AbhishekChoubey, GautamVarde “Contact stress analysis of spur gear” International

Journal of Engineering Research & Technology Vol.1, Issue.4, June 2012.

10. Ali Raad Hassan “contact stress analysis of spur gear teeth h pair” International journal of mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol.3, no.10, 2009.

ACKNOWLEDGEMENT We would like to thanks our BLDE engineering college principal and HOD of mechanical and Automobile engineering departments those who helped us to carry out this research and helped us to use the machines in workshop.

BIOGRAPHIES

Mr. I.G.Bhavi Assistant professor Department of Automobile Engineering, BLDE’As V.P.Dr.P.G.H College of engineering and Technology,Vijayapur ,Karnataka.

Mr. Sachin Almelkar PG student, M.Tech (machine Design), Department Of Mechanical Engineering BLDE’As V.P.Dr.P.G.H College of engineering and Technology,Vijayapur ,Karnataka.

comparison of analytical & fea of contact analysis of spur gear drive

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